Recently, following the rapid development of electronic semiconductor industries and the advance of manufacturing process technologies, there is a trend toward having various electronic products slimmer and slimmer in the market. To go with the trend, the electronic components of the electronic products are miniaturized, while the performances and operation capability of the electronic components are increased. When such as a notebook or a desktop computer operates, many electronic components generate high heat at the same time, especially the central processing unit (CPU). The heat must be efficiently dissipated outward. Otherwise, the temperature will rise very quickly to cause burnout of the electronic components. In order to avoid damage of the CPU, in general, a heat sink composed of a radiating fin assembly and a cooperative cooling fan is provided to dissipate the heat generated by the CPU and thus keep the CPU functioning normally. Therefore, the CPU heat sink has become a very important component in the current information industry.
Recently, water-cooling technology has been widely applied to personal computers to save the large volume radiating fin assembly. According to the water-cooling technology, the heat generated by the heat source of a system is absorbed by a working fluid. Then heat exchange takes place between the working fluid and the air under operation of a heat exchanger. The length of the pipeline is freely variable so that the heat exchanger (radiating fin assembly) can be more flexibly positioned without limitation of space. The water-cooling system necessitates a water reservoir and a pump for driving the working fluid to flow. Therefore, the entire system has the problems of reliability of the pump, leakage of the pipeline, etc. However, while being imperfect, the water-cooling heat dissipation technology is still the best option for heat management and control in the market. The water-cooling system is applicable to a desktop computer that has a larger volume and is free from limitation of space. However, the water-cooling technology can be hardly applied to a current lightweight and slim laptop. Therefore, at the present time, heat pipe and radiating fin assembly are still used in the laptop for heat transfer and heat exchange. Also, power consumption of the CPU of the laptop is required to be as lower as possible. Therefore, it is tried by the manufacturers to provide a heat dissipation measure with higher heat flux for satisfying the upcoming desperate heat dissipation demand.
In the conventional heat dissipation technology, heat pipe and vapor chamber (VC) are used as heat transfer components. When manufacturing the heat pipe and vapor chamber, the inner wall of the heat pipe is formed with a sintered body as a capillary structure. In the manufacturing process, metal (copper) particles or powders are filled into the inner wall and compacted. Then the heat pipe is fed into a sintering furnace to sinter the copper particles or powders into porous capillary structure for providing capillary attraction. The sintered body leads to a considerable thickness of the heat pipe and vapor chamber. As a result, it is impossible to slim the heat pipe and vapor chamber. In addition, the vapor chamber is formed with sintered wick, mesh or channel structure for providing capillary attraction to drive and circulate the working fluid in the heat pipe or vapor chamber. Such structure is manufactured in a quite complicated manner at higher cost.
Furthermore, it is critical to select a suitable wick structure for the vapor chamber. The wick structure must be able to keep the flow speed of the condensed liquid and have sufficient capillary attraction to overcome gravity. According to the aforesaid, the conventional heat pipe or vapor chamber has the following defects:
1. It is hard to process the conventional heat pipe or vapor chamber.
2. The conventional vapor chamber can be hardly slimmed.
3. The conventional heat pipe or vapor chamber is manufactured at higher cost.
4. It takes much time to manufacture the conventional heat pipe or vapor chamber.